From the specification of Danish patent No. 128.976 a method and an apparatus are known for moisture conditioning of tobacco in bunches in such a way that the leaves will substantially maintain their position in the bunch so that, even after termination of the treatment, the leaves will form orderly bundles or stacks in which all of the leaves are properly oriented and are relatively smooth. Therefore, without being manipulated (by being turned and smoothed) the leaves may be passed to further processing in cutting and rolling machines for being used as wrappers and binders in cigars and similar tobacco articles. This is achieved in such a way that after the removal of the strapping at the butt end of the bunch, the tobacco leaves in each bunch are held together by being pinched in a region extending across the width of the bunch and having such a distance from the ends thereof that on both sides of said region the leaves may spread in order to make it possible for water applied to them by spraying, or air blown towards them, to penetrate between the leaves. In order to enhance this possibility, the leaves in each bunch may be held together successively in two different regions suitably spaced in the longitudinal direction of the bunch.
When moisture conditioning tobacco either according to this method or by traditionally dipping the bunches into water and subsequently flinging off the excessive water, the tobacco should be pretreated by placing the bunches in perforated boxes in which they are subjected to warm stream, that is preferably sucked through the box. By this pretreatment, a certain softening of the leaves in the bunch is assured so that the leaves can better stand the subsequent treatment and, furthermore, the originally very compact bunch will, to a certain degree, be loosened by separation of the individual leaves outside the strapped neck of the bunch. An additional important factor is that the leaves are heated by the steam, thus making it easier for the liquid subsequently applied to penetrate into the leaves through the wax coating on their surfaces.
No matter how the moistening is carried out, the tobacco must be given possibility for setting, i.e. for water absorbed into the leaves to distribute uniformly to all parts of the leaves. For this purpose, the moistened bunches may be stored, e.g. for approximately 24 hours, in a warm and damp atmosphere, whereupon the humidity of the leaves, if necessary, may be finally adjusted by applying additional liquid or by removing excessive moist, before the tobacco is delivered for further processing, or is stored in a cooling store with controlled temperature and humidity conditions.
Thus, all things considered, the moisture conditioning is quite a lengthy process which requires considerable manual handling of the tobacco and, in addition to this, requires considerable store capacity because of the time necessary for the setting.